Obnoxious insurance commercials notwithstanding, the gecko has contributed a fair amount to human culture. In particular, scientists have long been fascinated by the reptiles’ foot pads, which give them the remarkable ability to climb on walls and ceilings. Over the past decade, a plethora of research institutions have attempted to replicate the effect, hoping to design a stronger, lighter adhesive material.
Leading the pack is University of Massachusetts Amherst, where researchers Al Crosby and Duncan Irschick have developed a proprietary adhesive called Geckskin. The biomimetic product--which looks like a coaster--synthetically replicates the gecko’s foot pads, which are covered in millions of microscopic hairs called setae. “Amazingly, gecko feet can be applied and disengaged with ease, and with no sticky residue remaining on the surface,” Irschick explains, mainly thanks to Van der Waals forces--the molecular bond between two objects close to each other.
Scientists had long attempted to replicate setae, but no one could get it quite right--primarily, because no one was looking at the gecko’s anatomy in full. Irschick, a functional morphologist who has spent two decades studying geckos, figured out that it wasn’t just the setae that made the foot pads strong; it was the rigid tendons beneath them, acting in unison with the soft hairs.
So Crosby and Irschick designed a multilayered pad that mimics the combo: a soft layer of a type of inexpensive silicone called polydimethylsiloxane, woven into a rigid layer giving the granular fabric the stability it needs to support huge weights. “Our contribution is to really look at the whole organism,” Crosby explains. “It allows the pad to drape over the surface, getting close enough that the Van der Waals interactions become strong.”
An index-card-sized square of the stuff can support 700 pounds to a glass wall, then easily peels off leaving zero residue. Obviously, such a product could have huge commercial appeal for companies selling everything from flatscreen TVs to adventure apparel. Geckskin™ is still a few years off, though. “We don’t have a product on the market, yet,” Crosby tells Co.Design, “but hopefully soon.” He adds that the team is carrying out another study--this one, of adhesion-based climbing organisms--that could contribute to other consumer products down the line. Says Irschick: “It shows the true integrative power of evolution for inspiring synthetic design."